Zerilli, 85, came forth last month and, in a televised interview with WDIV Channel 4, claimed that after Hoffa, who disappeared in the summer of 1975 from a restaurant parking lot in Bloomfield Township, was murdered, he was taken to a piece of property on Buell Road and buried underneath a barn that no longer exists.

Watch a report on the search for Hoffa on today's News at Noon.

At the time Hoffa vanished, the parcel of property, located in Oakland Township, was owned by convicted Detroit mob boss, Giacomo (Black Jack) Tocco, 85 of Macomb County and Zerilli's first cousin.

It is well known that Tocco and Zerilli, once best friends and business partners, are in a long-standing feud.

"There is no question Zerilli is the most credible witness to come forward in the Hoffa investigation," he said. "You might have some doubts about his motives and maybe even his sanity, but you have to check it out."

Carone spent more than two decades working organized crime for the FBI in Detroit, racking up countless hours specifically chasing the likes of Zerilli, Tocco and their associates.

In a massive racketeering case that came down in the 1990s that Carone helped build, the government convicted Tocco of being the "Godfather" of the Detroit Mafia and Zerilli of being his "Underboss" or No. 2 in charge.

Both served federal prison sentences and each have had their names attached to the Hoffa case in the past.

Hoffa went missing at around 3 p.m. on July 30, 1975. He was last seen leaving the parking lot of the Machus Red Fox restaurant, at the corner of Maple and Telegraph roads, in the passenger's seat of a maroon Mercury Brougham. That afternoon he was supposed to meet high-ranking mob chiefs Anthony "Tony Jack" Giacalone of Detroit and Anthony "Tony Pro" Provenzano of New Jersey at the restaurant in an attempt to resolve a dispute between Hoffa and the mob in relation to Hoffa's attempt to win back the Teamsters presidency, a post he relinquished earlier in the decade while serving a prison term for jury tampering, bribery and fraud.

In his second interview with WDIV on Sunday night, Zerilli, who himself was in prison the day Hoffa disappeared -- serving time on a conviction for skimming $6 million from a Las Vegas casino, said that he was informed of Hoffa's burial site by Giacalone, the Detroit crime family's "street boss" from 1960 until his death of natural causes in 2001.

Zerilli has met with the FBI and U.S. Attorney's Office on three separate occasions since late last year.